Manufacture of artlfigial roofing slate



o. J. oww. K MANUFACTURE 0F ARTIFICIAL ROOFING SLATE.

APPLICA-HON FILED DEC. 30| 1914.

Patented Aug. 1, 1916 WWNNDN,

"mig mg l/vl/f/vTo/f Owen Jones Owen ATTORNEY OWEN JONES OWEN,l OF'BLAENAU FESTINIOG, WALES.

Specification of Letters Patent.

MANFACTURE OF ARTIFICIAL ROOFING-S-LATE Patented Aue'. 1. 1916.

Application tiled December 30, 1914. Serial No. 879.659.

To 171 -whom 1' t may concern Be it known that; I. OwEx JoxEs Owns.

'ales. Great Britain. have invented new and useful Improvements in the Manufacture of A\rtificial fRoofing-Slate. of which the following isa full. clear. andexact description.

The object. of the invention is to provide certain-newl and'nsetul improvements in the manufacture,of artificial roofing slatey from waste slate material whereby the cost ot production is reduced to a minimum and the artificial roofing slate or. tile produced is ot' lasting quality and is practicallyrendered non-porous and hence notv liable to absorb inois'tiu'e when in use.

In order to accomplish the desired result. use is made of a method whereby the waste slate material is reduced to a 'coarse state and a portion thereof is reduced to a fine state, the two portions then being mixed dry with a binding material such as cement. and then thel mixture is again agitated with the addition of water-to forma plastic mass which is pressed by'a suitable press into slate form. and then this slate is permeated with silicate of sodimn and subsequently with ehlorid of calcium to forni an insoluble silicate of calcium. The artificial roofing slate produced by this method consists of a mixture of coarse and tine waste slate material.

ka binding substance and silicate of calcium.

ln order to carry `the above method into eect I prefecto use an apparatus such as shown in the accompanying drawings forming part of this specification. in which similar characters of reference indicate corresponding parts in both views. and in whichrl `igure 1 is a side elevation ot the apparatus: and Fig. 2 is a perspective view ot' one of the plates supporting a pressed slate.

The waste slate material is crushed into a coarse powder by the use ot' a suitable stone breaker or a crushcr ot any apprm ed coustruction. and about one-quarter otl the coarse powder is placed into a pulvcrizer or a mill B. which grinds the coarse powder into very tine powder. ln practice l have found that the best results are obtained b v reducing the slate material in tbc lrst stage into coarse or granular form. and a portion of this granular slate material is reduced to.

a tine or impalpable state. The coarse powder and the ine powder are next carried by an elevator or conveyer C to a screen l). preferably provided with tightly stretched piano wires to separate the tailings from the carse and fine powder and to return the tailings by achute E to the crusher The coarse and fine powder passes from the screen D through a hopper l'` into a mixing machine (l in which the powdersare inti mately mixed together with a suitable binding substance such as Portland Vcena-nt. `When the materials have been thoroughly mixed. they are discharged into a .second mixer H supplied with water through a suitable water supply pipe l to produce a plas..A

tic mass which is periodu-ally discharged into a press .l by which the plastic material is pressed into slatesf l( on top ot' plates l. of metal or other suitable material. ln practice each plate L is placed to one side ot' the press mold and with its surface (lush with the top of the mold. after which the mold is: filled with the plastic material and the latter is then subjected to pressure ot'. at least. two tons to the square inch. 'l`he pressed slate is next pushed out ot' the mold and onto the adjacent plate L. and then the above-descriled operation of pressing another slate is repeated. lt is desirable that I the plungers and mold of the press .l are heated'by steam or dampened and heated by injecting steam into them. The pressing of the slate is carried on at fthe rate of about nine pressings a minute in each mold. I find that the plates L are absolutely necessary when slates of sizes such as 16x-Q. lb'xfl or 20x10 inches. and still larger ones. are molded with only five-sixteenths of an inch. or even less. in thickness` The plate L with the slate K superimposed thereon next passes from the press J onto the endless conveyer belt .Y for carrying it to a drying room having a moist atmosphere at a normal temperature. say of G00. and well protected against draft. It is understood that the waste slate material in coarse powder form gives the desired strength to the slate or tile while the waste slate material in line powder form together with the Portland cement lills the iuterstices in the mixture to insure the subsequent formation of an exceedingly strong and solid slate or tile. .\s tle slate produced is but five-sixteenths ot' an mch or leven less in thickness it is evident that it made only ot' fine` powder slate material and cement it would lack the desired s rength.,

and if maid@ only. of coarse grain slate materialinterstices detrimental to the strength of the slate or tile would be formed; but by using a mixture of coarse gra-in slate material,fine grain slate material and cement the desired strength is obtained. By allowing the slate or tile to set in a moist atmosphere, as above described, the setting process takes place gradually and the particles are rmly bound together to produce the desired toughness in the slate or tile. The artificial slates ortiles at this stage although to all appearances quit-e marketable ha re one great detect as a rooting material, namely, they absorb water. In Order to render the slates non-porous use is made of a solution of silicate of sodium applied to the surface of each slate with a brush so that the solution rapidly soaks into the slate. 'hen the slate has been permeated with the solution then a solution of ehlorid of calcium is applied to the slate by the use of another brush, and whenthis solution has soaked into the slate then Whatever salt or other matter remains on the surface of the slate is wiped off with a. rag in order to prevent the formation of crystals on the surface of the slate.

'It is understood that b v reason of the re action of the one chemical on the other the uit " ores of the slate or tile are filled with a ard insoluble silicate of calcium, thus rendering the slate non-porous. lt is understood that by applying the solutions with abrush to the slate K while the latter rests material, fine 'waste slate material, cement and water. then pressing the resultant mixture while moist into 'the form of a slate and supporting the slate throughout itsunder surface, then drying the vslate in a moist atmosphere and while so supported filling the pores of the pressed slate with a silicate to render the slate insoluble and nonporous.

2. The herein described method for man ufacturing artificial roofing slate from waste slate material consisting in mixing coarse granulai` waste slate material, pulverized impalpable waste slate material and a binding substance, then moistening the mixture, then pressing the moistened mixture into a slate and supporting the slate throughout its under surface, then drying the slate in a moist atmosphere and while so supported, then saturating the slate with silicate of Soda and subsequently with chlorid of calcium to permeate the slate with silicate of calcium.

3. The herein described .method for producing artificial 'roofing slate from waste slate material, consisting in reducing the waste slate materialto coarse granular form, then reducing a portion of the said coarse granules into tine impalpable powder form, then mixing the coarse and fine slate` material with cement, then mixing the resultant dry mixture with water to form a plastic mass, then pressing the plastic mass into a slate and supporting the latter throughout its under side, then drying the slate in a moist atmosphere, then applying a solution of silicate of sodium to the slate to ,allow the said solution to soak in, andt'hen applying a solution of chlorid of calcium to the slate to soak in a'nd combine with the silicate of sodium to form a hard insoluble silicate of calcium filling the pores of the slate.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

OVEN JONES OlVEN. lVitnesses THEO. G. Hos'rea, PHILIP D. RoLLnAUs. 

